Ultra high frequency oscillator



Aug. 12, 1941. H. E. GOLDSTINE ULTRA HIGH FREQUENCY OSCILLATOR Filed Aug. 10, 1939 5 Sheets-Sheet l SUPPLY OUTPUT INVENTOR. AZLAN E. 60L DST/NE ATTORNEY.

5 Sheets-$heet 2 IIV VEN TOR. HA LL'AN E. GOLDST/NE A 'I'TORA'E Y.

GRID a/P M005 (L /P Aug. 12, 1941. H. GOLDSTINE ULTRA HIGH FREQUENCY OSCILLATOR Filed Aug. 10) 1939 Aug. 12, 1941. H. E. GOLDSTINE ULTRA HIGH FREQUENCY OSCILLATOR Filed Aug. 10, 1939 5 Sheets-Sheet 3 INVENTOR. HALLAN E. GOLD-STINE 7k A TTORNE Y.

2, 1941. H. E. GOLDSTINE ULTRA HIGH FREQUENCY OSCILLATOR Filed Aug. 10, 1939 v 5 Sheets-Sheet 4 INVENTOR. HALLAN' E. GOLD-STINE ATTORNEY Aug. 12, 1941. H. '5, GOLDSTINE 2,252,370

ULTRA HIGH FREQUENCY OSCILLATOR Filed Aug. 10, 1939 5 Sheets-Sheet 5 r0 HEATER/3.,

I NV EN TOR. HALL/1N E. 601.05 T/NE ATTORNEY:

Patented Aug. 12, 1941 ULTRA HIGH FREQUENfiY OSCILLATOR Hallan E. Goldstine, Port Jefferson, N. Y., as-

signor to Radio Corporation of America, a corperaticn of Delaware Application August I0, 1939, Serial No; 289,337 18 Claims. (Cl. 250-36) The present invention relates; to ultra high frequency electron discharge device systems. In particular, the invention relates to an ultra high frequency oscillation generation system and to an eflicient mechanical construction for the 1 same.

One of the'objects of the present invention is l to provide-a constructionfor an ultra high ire quen'cyoscillator systemwhich is suitable for. use

onfrequenciesof the order of 500.meg'acycles,

wherein one or several vacuum tubes may be em-' ployed depending on thepower output desired. Another object is to provide a novel: mechani calconstruction for an ultra high frequency sysuum tube oscillators, and another resonant concentric line in circuit with all of the filaments of these samevacuum tube oscillators. In order to conserve'spa'ce, among other things, it is preferred to employ the outer surface of one concentric line'as one conductor; of the other con-. ii

centric line." Another feature resides in the use of a single resonant concentric line'in' circuit with the control electrodes or grids Of a plurality of vacuum tube oscillators, and additional individual resonant lines for tuning the filaments vacuum tube oscillators.

Still further features of the invention relate to the mechanical constructions for deriving-output of these same power, and to the arrangements for grouping a 1' plurality of-'the'vacuum' tubes in parallel with a minimum of inductance in the electrode connections.

The novel constructional arrangement of the invention as herein describedhas been successfully used in generating power at 500 megacycles, althoughlit will be understood that the various elements thereof as well as the circuit as a whole may be .used in oth er circuitschemes. i

The following is a detaileddescription of the invention in conjunction with drawingsiwherein the same reference numerals "arei used throughout the figures to designate the same Darts. I l

Fig. 1 is a schematic circuit diagram of an ultra highire u'ency oscillator system in accordends with one embodiment 'of'the' invention employing a single resonant concentric lineto control the frequencies of a plurality of vacuum tubes in electrically parallelk'relation, andanother resonant concentric line in common with the filaments of these parallel connected tubes;

Fig.2 is a front elevation of the complete mechanical construction employed for the oscillator system of Fig. 1;

Fig. 3 is a rear elevation of any quarter of the mechanical construction of Fig. 2, it being understood that all quarters are alike;

Fig. 4 is a section of Fig. 2 along the line 4-4;

. Fig. 5- is a perspective View of a filament coupling loop employed for each vacuum tube in the system of Figs. 1 and 2; i

Fig. 6 is a section oi a unit employed in the mechanical construction for accommodating the grid choke coil and anode sleeve connection for each vacuum tube oscillator; I Fig. 7 is a schematic circuit diagram of another embodiment of the invention employing individual concentric lines for tuning the filaments of the vacuum tube oscillators;

Fig. 8 is a front elevation of any quarter of the complete mechanical construction for the circuit of Fig. '7, it being understood that all quarters are alike; 3 i

Fig. 9 is a'rear elevation of any quarter of the complete mechanical construction for the circuit of Fig.7; r I Fig-l0 is a fragmentary side view of the mechanical construction for Fig. 7, showing in section details of one of the individual-filament concentric lines. In effect, Fig. 10 shows half of-the construction of Fig. 4, modified to omit the common outer concentric line and to include the individual concentric line; and

Fig. 11 is a section of one of the filament concentric lines of the circuit of Fig. '7.

Referring to Fig. 1 in more detail, there is shown a low loss, resonant concentric line comprising aninner conductor I and an outer conductor 2, to the inner conductor of which are inductively coupled through coils 3, 3 four individual short wave oscillation generator vacuum tubes 4, 4. The resonant concentric line I, 2 is generallyof the type described in the article by Clarence WV. Hansell, published in the A. I. E. Transactions of August, 1935, pages 852 lac-857; Each vacuum tube oscillator comprises anwanode 5, "a control electrode or grid-6, anda filament 1.:to" thegrid ofwhich is connecteda tuned U-sha-ped loop,- herein designated schematicallyas 3. The terminals forthe anode and grid electrodesJot each of these vacuum tubes extend; from these electrodes through opposite sides ofithe envelope; so asto minimize lead connections, Whilethefilament lea s of each vacuum tube extend through one end of the envelope. The general configuration of these vacuum tubes 4, 4 are shown in more detail in Fig. 2, which will be described later. The grid circuits of the vacuum tubes are by-passed to ground by capacitors 8, 8 and supplied with suitable negative direct current bias through choke coils 9, 9 which, taken together with capacitors III, III, form filters for preventing radio frequency fluctuations on the grids from entering the direct current power supply. The anodes of the vacuum tubes are grounded for radio frequency energy by means'of by-pass capacitors II, II. The filaments of the vacuum tubes are all coupled in common through loops I2, I2 to a single concentric line formed from the outer surface of conductor 2 and a surrounding cylindrical conductor I3. The active parts of the filaments are maintained at a radio frequency potential and this potential is determined by means of tuning the filament reactance. The center of each filament is coupled to ground through a capacitor I6 which'serves to tune out the reactance of the filament leads. The outer legs of each filament are by-passed to the loop I2 and thence to ground, while heating energy for the filament is obtained from leads II which extend through the loop I2, as shown. In this way the filament of each tube fioats above ground potential. j From what hasbeen stated above, it will be apparent that the low loss resonant line I, 2 is the frequency stabilizing tank circuit for all vacuum tubes, and that the filament tuning circuit constitutes in effect regeneration coils, the regeneration being changed by tuning the fi1a merit circuit. Feedback is efiected through the interelectrode capacity between grid and filament in each tube. An advantage of the arrangement of the invention is that the oscillation generation system will function even though one or more of the vacuum tubes fail to function.

Output energy from the oscillation generation system is derived from loop I4 coupled to the common filament concentric line. Condenser I located across the conductors 2, I3 of the filament concentric line serves to tune the filament concentric line to the operating frequency.

The mechanical details of the construction embodying the circuit of Fig. 1 are shown in Figs. 2, 3, 4, 5 and 6. Fig. 2 is a front elevation of the complete mechanical construction of the oscillation generation system, while Fig. 4 is a section of Fig. 2 along line 4-4, showing in detail the construction of the two resonant concentric lines.

Fig. 2 shows clearly the general arrangement of the preferred form of vacuum tubes 4, 4, each of which has two anode prongs A, A and two grid prongs G, G. Only two of th four vacuum tubes 4, 4 have been shown in Fig. 2 in order to simplify the drawing and to better show the details of themechanical construction. The anode and grid prongs have individual clips mounted on the face or end plate I9 which end plate couples together the inner and outer conductors I, 2 and 2, I3. The'vacuum tubes are mounted on metallic strips IB, I8 arranged around a circle and insulated from each other and from the end plate I9. The'metallic strips I8; I8 are insulated for anode direct-current voltage from end plate I9 by thin mica sheets, thus forming radio frequency by-pass condensers to maintain these strips at very low radio frequency potential. Each strip I8 is provided with an indented portion in its center to permit the vacuum tube to be mounted as near to the end plate I9 as possible. Screws 2|], 2!! located within insulating bushings serve to securely mount the strips I8, I8 upon the end plate. The two anode terminals or prong clips for each vacuum tube are in direct current conductive engagement with the strip I8 accommodating the vacuum tube. The two grid terminals for each vacuum tube are insulated from the strip I8 and from the end plate I9 and are connected together in the interior of the concentric line I, 2 by means of a sector shaped metallic plate 2| which is folded over in the form of a right angle to constitute the loop 3 coupling the grid to the inner conductor I. The direct connection between the grid terminals and the direct connection between the anode terminals for each vacuum tube reduces the lead inductances of grid and anode electrodes to a minimum, and reduces the deleterious effects of the lead impedances. The rear view of plate 2| is shown in Fig. 3 which illustrates how the wide ends of the plate 2| make direct contact with the grid clips. The U-shaped loop 3 is completed by means of a metal plate 22 in direct contact with angle plate 2| but insulated from the end plate I9 by means of a mica spacer 23. Fig. 4 shows in section a side view of grid loop 3 and its associated elements. The grid loop 3, in turn, is connected by a metal strip 24 to a filter can containing therein a choke coil 9 in series with the grid connection 24 (note Figs. 3 and 6). The sleeve or shield of the filter can, labeled I I, is in direct contact at one end with its associated metallic strip I8, and serves as the anode connection for supplying the anode of the vacuum tube with a positive polarizing potential. The sleeve II is insulated from the terminals for the choke coil 9 and from the end plate I9 and forms with the end plate a by-pass capacitor '(labeled II in Fig. 1), thus grounding the anode for radio frequency energy. It should be noted that the anode clips of each vacuum tube are directly mounted upon and are in direct contact with its associated strip I8, while the grid clips on the other hand do not contact strip I8.

The three filament leads for each vacuum tube extend from one end of the tube envelope and are inserted into individual prong clips 25, 25 forming an integral part of the filament metallic tuning loop I2. (Note Fig. 5.) These elements 25, 25 terminate in small metal segments 26, 26 which are insulated from each other and form low impedance by-pass capacitors with each other. The central segment 26 makes contact from a direct current standpoint both with the hollow metallic loop I2 and with that filament lead which extends to the center point of the filament. The outer segments connect with the legs of the filament and with the heater wires I! which are located in the interior of the hollow loop I2. The three segments 26, 26 form a capacity with a stud 21, which is adjustable by a screw 28. By adjusting screw 28, I am able to tune the filament leads so as to obtain the proper oscillating voltage. The loop I2 is mounted on a metallic stud 35 which is insulatingly supported from the end plate I9.

For tuning the filament concentric line 2, I3 there is provided a metallic plate I5 in direct contact with cylinder I3 and adjustable by knob 29 to vary the capacity between conductors 2 and I3. The plate I 5' is located at a high impedance point on the filament concentric line where it has a maximum effect.

The concentric line 2, I3 extending from end plate I 9 to end plate 30 is electrically one-half wavelength long at the operating frequency. It will thus be seen that the capacitor formed by plate l5"-is located at a place where the current in the line is low and the impedance is high, while the filament loops l2 are located at places where the current in the line is high, corresponding to a low impedance point.

. The inner conductor of concentric line I, 2

is shown provided with a metallic bellows 3| and an Invar rod 32 for maintaining the overall length of the inner conductor I substantially constant with change in temperature. As is known, the Invar rod has a low temperature coefficient of expansion characteristic. A knurled knob 33 and a spring arrangement 34 enables adjustment in length of the inner conductor in either direction. The overall length of the inner conductor I including bellows is made to be electrically approximately one-quarter of a wavelength long at the operating frequency.

Fig. 7 is a schematic circuit diagram illustrating a modification of the oscillation generation system of Fig. 1, and differs from Fig. 1 mainly in the provision of individual tuned; circuits for the filaments of the vacuumtubes. Instead of the common concentric line ,2, l3 employed in Fig. 1 for all of thevacuum .tubefilaments, there is provided in Fig, 7, separate low loss concentric line resonators for thefilaments of the tubes. With this exception, the circuit and mechanical construction of Fig. 7 is substantially identical with that of Fig. 1, and the same parts in both figures are labeled with the same reference numerals.

Each vacuum tube 4 of Fig. '7 has its filament 1 tuned by means of a concentric line comprising an inner tubular conductor 36 and an outer grounded tubular conductor 31, the Iconductors being directly connected together at the end of the line removed from the filament. Both conductors 36, 31 are tuned by means of a slider 38 which contacts the outer surface of 35 andthe inner surface of 31- and is movable over the lengths of these conductors. The heater leads I! for the legs of thefilament I. extend within the interior of the inner conductor 36 and are capacitively coupled to the inner conductorat the end of the line nearest theufilament by means of by-pass condensers 39, .39 and also capacitively coupled to the outer conductor 31 at the endof the concentric line farthest away from the filament by by-pass condensers 4! .4 3, thus providing paths of low impedance to these conductors for energy of the operating frequency. The connection from the mid point of each filament extends. directly to the end of the inner conductor nearest thefilament.

Output energy isderived from-the oscillation generation system in any suitable fashion, preferably by a connection 4| to one of the filament concentric lines, as shown. In order to couple the oscillation system to a symmetrically .arranged or balanced output circuit, the connection M is divided at point into two conductors 43, 44 which differ in length from each other by one-half wavelength, thus providing on conductors 43, 44 currents of equal intensity and opposite phase which are symmetrical with -re-. spect to ground. 7 1 i The constructional arrangementof the 01rcuit of Fig. 7, insofar as it difiers from'that for Fig. 1, is shown in Figs. 8, 9,10 and 1l. Fig. 8 shows the front elevation View and Fig. 9 the rear elevation view of any quarter of the com-L plete mechanical construction, all .quartersbeihg alike. Fig. 1.0:is a fragmentary sidelview of onehalf ofthe mechanical construc-tion for Fig. 7. Fig. 11 showsqoneof; the filament concentric lines of Fig. 'Iindetail. L

Aninspection of those figures will: show that the individual 1 filament. concentric lines are mounted on and :around the'periphery of. cylin dricallconductor 2, thebuter conductor 31 of each filament concentric line being supported at one end by endplate' l9 and at another pointin its length by a supporting stud 4.5. The three filamentleads for each filament extending from one end of thevacuum tube are secured at one end of the filament concentric. linetdindi-vidual metallicplates 26., 26 by screws 46. Plates 26, 26' are insulated from each other and;exc'ept for the central plate 26', are also insulated from the inner conductor 36- The central plate: 23" is directly connected to the end of the inner conduct'or 36. The outer plates'2BQ26' are connected to the legs .of t'hefilament and also to the heater wires :l'l. :"Ihe effect of the mechanical arrangement of p1atesf2-6'; 26. is to provide .capacitive paths of extremely rlow impedance to radio frequency-energy betweenthe outer'p'lates 26'; 26' andthe nearest end of-"the inner conductor it. At the other end ofwthe filament concentric line. the. inner and outer conductors 36 and 31 are directly connected togetheriand capacitively coupled to the heater leads I] to form by-pass condenserspas shown. The 'movable slider 38 in the interior of the filament concentric line may consist of two pair of metallic sliding spring contacts '8, S which are electrically connected to acentral disc-like ring R contacting both conductors of the'line. One or more screws 41 projecting through slots in the outer conductor, are used to adjust the position of the movable slider; l I I What is claimed is:

1. An oscillationgeneration system comprising a plurality of vacuum tube oscillators, a single' concentric line resonator coupled in electrically parallel relation to the inputs of said tubes for controlling the frequency thereof, tuning means coupled to the filaments of said vacuumtubes, and means; for deriving output energy from said last tuning means.

2. An oscillation generation system comprisinga plurality of vacuum tubes; each having a grid and a'filament, a concentric line resonator coupled to the grids of said vacuum tubes, a hollow conductor surrounding saidline resonator, said conductor together with the outer surface of said line resonator forming a low loss tuned circuit, and means for coupling the filaments er said vacuum tubes'in common to said low loss tuned circuit. r 1

3. A system-in accordance with claim 2, characterizedinthis that said concentric line resonator isefiectively one-quarter wavelength long centric line resonator having an inner and an outer conductor, a loop inductively coupling the grid of each tube to said line resonator, whereby saielline resonatorcontrolsthefrequency of all of said oscillators, a capacitive connection from the anode of each vacuum tube to ground for energy of the operating frequency, and another concentric line resonator constituted by a hollow tubular conductor which surrounds said outer conductor and combines with the outer surface of said outer conductor to form another tuned circuit, and means inductively coupling the filament of each vacuum tube oscillator to said last concentric line resonator.

5. An oscillation generation system comprising a plurality of vacuum tube oscillators each having a grid, a-filament and an anode, a concentric line resonator having an inner and an outer conductor, a loop inductively coupling the grid of each tube to said line resonator, whereby said line resonator controls the frequency of all of said oscillators, a capacitive connection from the anode of each vacuum tube to ground for energy of the operating frequency, and another concentric line resonator constituted by a hollow tubular conductor which surrounds said outer conductor and combineswith the outer surface of said outer conductor'to form another tuned circuit, a loop inductively coupling the filament of each vacuum tube to said last concentric line resonator, and means for tuning out at least a portion of the reactance of the filament leads, whereby the active part of each filament is maintainedat a desired radio frequency potential.

6. 'An oscillation generation system comprising a plurality of vacuum tube oscillators each having a grid, a filament and an anode, a concentric line resonator having an inner and an centric line resonators being provided with means 1 individual thereto for changing the reactance thereof.

7. An oscillation generation system comprising a plurality of vacuum tube oscillators each having a grid, a filament and an anode, a concentric line resonator having an inner and an outer conductor, a loop inductively coupling the grid of each tube to said line resonator, whereby said line resonator controls the frequency of all of said oscillators, a capacitive connection from the anode of each vacuum tube to ground for energy of the operating frequency, and another concentric line resonator constituted by a hollow tubular conductor which surrounds said outer conductor and combines with the outer surface of said outerconductor to formanother tuned circuit, said inner conductor of said first concentric line resonator being electrically one-quarter of the length of the operatingwave, said last concentric line resonator having an effective electrical length equal to one-half of the length of the operating wave, and. means inductively coupling the filaments of said vacuum tube oscillators to points of low impedance on said last concentric line resonator.

8. An oscillation generation system comprising a plurality of vacuum tube oscillators each having an anode, a filament and a grid, a single concentric line resonator coupled in electrically parallel relation to the grids of said tubes for controlling the frequency thereof, a capacitive low impedance connection from each anode to a point of zero radio frequency potential, and additional concentric line resonator means coupled to the filaments of said vacuum tube oscillators, said additional resonator means being adjustable in length for tuning.

9. An oscillation generation system comprising a plurality of vacuum tube oscillators each having a grid and a filament, a single concentric line resonator for controlling the frequency of said vacuum tubes, said resonator having an inner conductor and an outer conductor coupled together through an end plate, said vacuum tubes being mounted on the exterior surface of said end plate around the center thereof, connections from the grids of said vacuum tubes extending into the interior of said line resonator for coupling thereto, and means located externally of said line resonator for tuning the filaments of said oscillators.

10. An oscillation generation system comprising a plurality of vacuum tube oscillators each having a grid and a filament, a single concentric line resonator for controlling the frequency of said vacuum tube oscillators, said resonator having an inner conductor and an outer conductor coupled together through an end plate, said vacu um tube oscillators being mounted on the exterior surface of said end plate around the center thereof, connections from the grids of said vacuum tubes extending into the interior of said line resonator for coupling thereto, a capacitive path of low impedance to energy of the operating frequency from each anode to said end plate, and low loss resonator means positioned around said line resonator for tuning the filaments of said oscillator.

11. An oscillation generation system comprising a plurality of vacuum tube oscillators, a resonator coupled in electrically parallel relation to the inputs of said tubes for controlling thefrequency thereof, tuning means coupled to the filaments of said vacuum tubes, and'means for deriving output energy from said last tuning means.

12. An oscillation generation system comprising a plurality of vacuum tube oscillators, a resonator coupled in electrically parallel relation to the inputs of said tubes for controlling the frequency thereof, tuning means coupled to the filaments of said vacuum tubes, and means for deriving output energy from said last tuning means, said vacuum tubes being mounted on said resonator.

13. An oscillation generation system comprising a plurality of vacuum tube oscillators each having a grid, a filament and an anode, a concentric line resonator having an inner and an outer.

conductor, a loop inductively coupling the grid of each tube to said line resonator; whereby said line resonator controls the frequency of all of said oscillators, a capacitive connection from the anode of each tube to ground for energy of the operating frequency, and another concentric line resonator constituted by a hollow tubular conductor which surrounds said outer conductor and combines with the outer surface of said outer conductor to form another tuned circuit, and means inductively coupling the filament of each vacuum tube oscillator to said last concentric line resonator, said last concentric line having an effective electrical length equal to half the length of the operating wave.

14. An oscillation generation system comprising a plurality of vacuum tube oscillators each having an anode, a filament and a grid, a single concentric line resonator coupled in electrically parallel relation to the grids of said oscillators for controlling the frequency thereof, a capacitive low impedance connection from each anode to a point of zero radio frequency potential, additional concentric line resonator means coupled to the filaments of said vacuum tubes, said additional resonator means being adjustable in length for tuning, and means for deriving output energy from said last means.

15. An oscillation generation system comprising a plurality of vacuum tube oscillators each having a grid and a filament, a single concentric line resonator for controlling the frequency of said vacuum tubes, said resonator having an inner conductor and an outer conductor coupled together through an end plate, said vacuum tubes being mounted on the exterior surface of said end plate around the center thereof, connections from the grids of said vacuum tubes extending into the interior of said line resonator for coupling thereto, a path of low impedance to energy of the operating frequency from each anode to said end plate, low loss resonator means positioned around said line resonator for tuning the filaments of said oscillators, and a circuit for deriving output energy from said means.

16. An oscillation generation system comprising a plurality of vacuum tube oscillators each having a grid and a filament, a single concentric line resonator for controlling the frequency of said vacuum tubes, said resonator having an inner conductor and an outer conductor coupled together through an end plate, a metallic element individual to and supporting each vacuum tube and insulatingly mounted on the exterior surface of the end plate of said resonator, a connection from said element to the anode of the vacuum tube which it supports, an electrically conducting sleeve electrically and mechanically connected to each metallic element, a choke coil insulatingly positioned within each sleeve, and a connection from each choke coil to the grid of that vacuum tube which is supported by the metallic element connected to the sleeve surrounding that particular coil, and means for maintaining each sleeve at a positive potential and its enclosed choke coil at a negative potential relative to the cathode of its associated vacuum tube.

1'7. A system in accordance with claim 16, characterized in this that said metallic element is capacitively coupled to the end plate of said resonator to provide a low impedance path thereto for energy of the operating frequency.

18. An oscillation generation system comprisin a plurality of vacuum tube oscillators each having an anode, a filament, and a grid; a resonator coupled in electrically parallel relation to the grids of said oscillators for controlling the frequency thereof; a capacitive low impedance connection from each anode to a point of zero radio frequency potential; resonator means adjustable for tuning purposes coupled to the filaments of said vacuum tubes; and means for deriving output energy from said last resonator means.

HALLAN E. GOLDS'I'INE. 

